U.S. Pat. No. 5,402,339 discloses a system for creating a music data base of musical information that can be processed by a computer and for retrieving a string of note data items from the music data base.
The known system comprises an input converter that converts music data supplied by an electronic device into note data items. The electronic device that supplies the music data is a computer, an electrical musical instrument, a music sampler or a reproducing device. Each note data item represents a time period and a scale degree of a sound identified by a single musical note. Both period and scale degree have digital values. The system further comprises a position information unit for producing position data items that specify the relative position in a sequence of the note data items in the piece of music represented by the music data. The note data items and position data items are stored together with an index table that links the data note items, the position data items, and the number of times a specific data note item occurs in the piece of music thus stored.
The known system comprises means to retrieve a particular piece of stored music. Music information is supplied to the system as a string of note data items and associated position data items. A particular seek algorithm is employed to find a match between the string and a particular piece of music. The algorithm uses a histogram for each theme specifying the number of times a particular note occurs in this theme. The query for a matching theme is then facilitated by focusing on the rarest notes as the characterizing elements of the theme.